Evaluating the Effectiveness of Nirsevimab in Reducing Pediatric RSV Hospitalizations in Spain
Sara Jimeno, Adrián Peláez, Agustín Labourt, Florencia Mercedes Acuña, Lucía Linares, Isabel Llana Martín, Ángeles Calle Gómez, S. Martinez
Abstract
Background/Objectives: Respiratory syncytial virus (RSV) is a major cause of hospitalization in infants. Nirsevimab has demonstrated to be a promising tool for preventing severe RSV disease. Although clinical trials have demonstrated the efficacy of Nirsevimab in preventing severe RSV disease, evidence regarding its performance in real-world clinical settings is still limited due to its recent introduction. This study aims to fill this knowledge gap by evaluating the impact of Nirsevimab in a cohort of infants and determining its effectiveness in reducing the burden of RSV disease. Methods: A retrospective study of RSV hospitalizations was conducted in children under six months of age, between 1 October and 31 March, across four seasons: pre-COVID (2018–2019), COVID (2019–2020), post-COVID pre-Nirsevimab (2022–2023), and Nirsevimab season (2023–2024). Results: Nirsevimab demonstrated significant efficacy in reducing RSV-related hospitalizations in infants under six months of age. During the 2023/2024 season, following the introduction of Nirsevimab, there was a substantial reduction in RSV-related lower respiratory tract infection (LRTI) hospitalizations. Among infants under 3 months of age, hospitalizations decreased by 79.3% (IRR: 0.21, 95% CI: 0.12–0.34). In infants aged 3 to 6 months, there was a 66.9% reduction (IRR: 0.33, 95% CI: 0.15–0.64). Additionally, Nirsevimab decreased the severity of RSV cases with LRTI who required the support of equipment for sanitary use, further reducing overall healthcare burden. Conclusions: These results underscore Nirsevimab’s vital role in preventing severe RSV infections and hospitalizations, especially among the most vulnerable infants, positioning it as a critical advancement in pediatric respiratory care.